S THE NAUTILUS. 



Family Margaritanidce 

 Margaritana margaritifera (Linn6) 



Family Sphaeriida. 



Spharium striatinum (La- Pisidium variabile Prime. 



marck) Pisidium compressum Prime. 



Sphcerium vermontanum Pisidium compressum Icevigatum 



Prime. Sterki. 



Musculium securis (Prime) Pisidium henslowanum 

 Musculium rosaceum (Prime) (Sheppard) 



Pisidium ferrugineum Prime. Pisidium, 4 undet. spp. 

 Pisidium xquilaterale Prime. 



CLASS GASTROPODA. 



Family Viviparidse. 

 Vivipara contectoides W. G. Campeloma decisum (Say) 



Binney. Campeloma integrum (DeKay) 



Family Amnicolidae. 



Amnicola limosa (Say) Somatogyrus subglobosus (Say) 



Amnicola lustrica Pilsbry Gillia altilis (Say) 



Amnicola lustrica Pilsbry, Bythinia tentaculata (Linn6) 

 variety 



Family Valvatidee. 



Valvata tricarinata (Say) Valvata bicarinata normalis 



Walker 



Family Pleuroceridx. 

 Goniobasis livescens (Menke) 



Family Physidee. 



Physa ancillaria warreniana Physa Integra Haldeman. 

 (Lea) Physa gyrina Say 



Family Ancylidse. 



Ancylus tardus Say Ancylus parallelus Haldeman. 



Ancylus fuscus C. B. Adams. 



